The present disclosure generally relates to a method of forming a semiconductor structure, and particularly to a method of forming replacement gate structures employing multiple types of disposable gate structures.
Conventional methods for integrating more than one type of workfunction material in replacement gate structures employ some type of patterning of workfunction materials after deposition within gate cavities. Such methods result in non-uniformity in the workfunction material thickness in the replacement gate stack structures depending on the channel length and the pitch of short channel devices due to the non-uniformity of the etch process employed to pattern the workfunction materials. Thus, an integration scheme is desired that can provide replacement gate devices including a workfunction material layer having a geometry-independent uniform thickness.